Single loop multistage fuel production

Abstract

Synthetic fuels are produced from synthesis gas in a four-stage reactor system with a single recycle loop providing the requisite thermal capacity to moderate the high heat release of the reactions and to provide the reactants and reaction environments for the efficient operation of the process. The first stage converts a portion of the synthesis gas to methanol, the second stage converts the methanol to dimethylether, the third stage converts the methanol and dimethylether to fuel and the fourth stage converts the high melting point component, durene, and other low volatility aromatic components such as tri- and tetra-methylbenzenes to high octane branched paraffins.

Description

FIELD OF THE INVENTION[0001]This invention relates to a new process to directly produce transportation fuels, such as gasoline, jet fuel and diesel from synthesis gas containing principally carbon monoxide, carbon dioxide, and hydrogen.BACKGROUND OF THE INVENTION[0002]The prior art describes several alternatives to produce gasoline and distillate from synthesis gas that do not anticipate the present invention of four reaction stages with an overall recycle loop to produce commercial quality fuels. Chang et al (U.S. Pat. No. 3,894,102) and Zahner et al (U.S. Pat. No. 4,011,275) propose that synthesis gas be passed over methanol producing catalyst with an acid component activity to convert methanol to dimethylether and then feeding this intermediate mixed product to a fuel producing stage with recycle of light components to mix with the intermediate mixed product feed.[0003]In another example, Chang et al (U.S. Pat. No. 4,076,761) use synthesis gas produced from coal, shale and / or res...

AI Technical Summary

Benefits of technology

This patent describes a new process to make transportation fuels directly from synthesis gas containing carbon monoxide, carbon dioxide, and hydrogen. The process involves four sequential catalytic stages with intermediate heat exchange, but without interstage separation. The unreacted gases from the fourth stage are recycled to the first stage, which enhances the conversion of the synthesis gas. The recycle also acts as a heat sink for the highly exothermic reactions involved in each stage. This process operates at high pressure, resulting in high reactor utilization efficiencies. Unlike previous methods, this invention uses high concentrations of carbon monoxide in the recycle gas, which allows for the use of a variety of catalysts. The hydrotreating reactions in the fourth stage are carried out in the presence of high concentrations of carbon monoxide, which is commonly taught to poison catalysts.

Problems solved by technology

In the Mobil MTG process, durene is produced in enough quantities to result in undesirable cold temperature performance of the gasoline and must consequently be reduced.

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